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', on_finish: function(trial_data){ // let's imagine that the correct answer is NO for both trials var correct = (trial_data.key_press == 78); jsPsych.data.addDataToLastTrial({correct: correct}); } } ``` --- ## jsPsych.data.addProperties ``` jsPsych.data.addProperties(properties) ``` ### Parameters Parameter | Type | Description ----------|------|------------ properties | object | Object of key: value pairs to add to the data. ### Return value Returns nothing. ### Description This method appends a set of properties to every trial in the data object, including trials that have already occurred and trials that have yet to occur. You can use this to record things like the subject ID or condition assignment. ### Examples #### Assigning a subject ID ```javascript jsPsych.data.addProperties({subject: 1}); jsPsych.init({ experiment_structure: exp }) ``` --- ## jsPsych.data.dataAsCSV ``` jsPsych.data.dataAsCSV() ``` ### Return value Returns a string in CSV format ### Description Generate a CSV formatted string containing all of the data generated in the experiment. ### Examples #### Basic example ```javascript var csvString = jsPsych.data.dataAsCSV(); ``` --- ## jsPsych.data.dataAsJSON ``` jsPsych.data.dataAsJSON() ``` ### Return value Returns a string in JSON format ### Description Generate a JSON formatted string containing all of the data generated in the experiment. ### Examples #### Basic example ```javascript var jsonString = jsPsych.data.dataAsJSON(); ``` --- ## jsPsych.data.displayData ``` jsPsych.data.displayData(format) ``` ### Parameters Parameter | Type | Description ----------|------|------------ format | string | Specifies whether to display the data in `'csv'` or `'json'` format. ### Return value Returns nothing. ### Description Outputs all of the data collected in the experiment to the screen in either JSON or CSV format. This is a useful method for quick debugging when developing an experiment. ### Examples #### Using the on_finish callback function to show data at the end of the experiment ```javascript jsPsych.init({ experiment_structure: exp, on_finish: function() { jsPsych.data.displayData('csv'); } }) ``` --- ## jsPsych.data.getData ``` jsPsych.data.getData() ``` ### Parameters None. ### Return value Returns an array containing all of the data generated in the experiment. Each element of the array contains the data for a single trial. Each trial's data is stored as an object in `key: value` format. ### Description Gets all of the data generated by the experiment. ### Example ```javascript var alldata = jsPsych.data.getData(); ``` --- ## jsPsych.data.getDataByTrialIndex ``` jsPsych.data.getDataByTrialIndex(trial_index) ``` ### Parameters Parameter | Type | Description ----------|------|------------ trial_index | numeric | The global trial index of the trial ### Return value Returns an array containing all of the data for a particular trial. Trials are automatically indexed by a global ### Description Gets all the data generated from a specific trial. ### Examples #### Basic example ```javascript var first_trial_data = jsPsych.data.getDataByTrialIndex(0); var second_trial_data = jsPsych.data.getDataByTrialIndex(1); ``` --- ## jsPsych.data.getLastChunkData ``` jsPsych.data.getLastChunkData() ``` ### Return value Returns an array containing all of the data generated in the same chunk as the last trial. Each element of the array contains the data for a single trial. Each trial's data is stored as an object in `key: value` format. ### Description Gets all of the data generated in the same chunk as the last trial. ### Example ``` var lastchunkdata = jsPsych.data.getLastChunkData(); ``` --- ## jsPsych.data.getLastTrialData ``` jsPsych.data.getLastTrialData() ``` ### Return value Returns an object in `key: value` format containing the data from the last trial. ### Description Gets the data generated by the last trial. ### Example ``` var lasttrialdata = jsPsych.data.getLastTrialData(); ``` --- ## jsPsych.data.getTrialsFromChunk ``` jsPsych.data.getTrialsFromChunk(chunk_id) ``` ### Parameters Parameter | Type | Description ----------|------|------------ chunk_id | string | The id of the chunk to get data from. ### Return value Returns an array containing all of the data generated in a specified chunk. Each element of the array contains the data for a single trial. Each trial's data is stored as an object in `key: value` format. ### Description Get all the data generated by a specified chunk. ### Example ```javascript var current_chunk_id = jsPsych.currentChunkID(); var data_from_current_chunk = jsPsych.data.getTrialsFromChunk(current_chunk_id); ``` --- ## jsPsych.data.getTrialsOfType ``` jsPsych.data.getTrialsOfType(type) ``` ### Parameters Parameter | Type | Description ----------|------|------------ type | string | Which plugin to get trial data from. ### Return value Returns an array containing all of the data generated by a particular plugin. Each element of the array contains the data for a single trial. Each trial's data is stored as an object in `key: value` format. ### Description Gets all the data generated by trials from a particular plugin. ### Examples #### Basic example ```javascript var all_xab_trials = jsPsych.data.getTrialsOfType('xab'); ``` #### Compute average RT over whole experiment ```javascript // this example shows how this method could be used to display data // to the subject, by finding all trials of type 'single-stim' and // calculating the average response time. var debrief_block = { type: "text", text: function() { return "Your average response time was " + getAverageResponseTime() + "ms. Press " + "any key to complete the experiment. Thank you!
"; } }; function getAverageResponseTime() { var trials = jsPsych.data.getTrialsOfType('single-stim'); var sum_rt = 0; var valid_trial_count = 0; for (var i = 0; i < trials.length; i++) { if (trials[i].rt > -1) { sum_rt += trials[i].rt; valid_trial_count++; } } return Math.floor(sum_rt / valid_trial_count); } ``` --- ## jsPsych.data.getURLVariable ``` jsPsych.data.getURLVariable(var_name) ``` ### Parameters Parameter | Type | Description ----------|------|------------ var_name | string | Which variable to get the value of. ### Return value Returns the value of a variable passed in through the query string. ### Description For extracting a particular variable passed in through a URL query string. ### Examples ```javascript // if the URL of the page is: experiment.html?subject=1234&condition=test console.log(jsPsych.data.getURLVariable('subject')) // logs "1234" console.log(jsPsych.data.getURLVariable('condition')) // logs "test" ``` --- ## jsPsych.data.localSave ``` jsPsych.data.localSave(filename, format) ``` ### Parameters Parameter | Type | Description ----------|------|------------ filename | string | Filename of locally saved file format | string | Specifies either `'csv'` or `'json'` format ### Return value Returns nothing. ### Description Saves a CSV or JSON file on the computer running the experiment. If conducting an online experiment, this will download the file onto the subject's computer, and is therefore not a recommended data storage solution for online data collection. **Warning:** This function relies on features which are [currently not supported by all major web browsers](http://caniuse.com/#search=createObjectURL), though adoption rates are increasing rapidly. It will work on the most recent versions of Chrome, Firefox, Safari, and Internet Explorer. ### Example ```javascript jsPsych.data.localSave('mydata.csv', 'csv'); ``` --- ## jsPsych.data.urlVariables ``` jsPsych.data.urlVariables() ``` ### Return value Returns an object (associative array) of the variables in the URL query string. ### Description For extracting variables passed in through a URL query string. ### Examples ```javascript // if the URL of the page is: experiment.html?subject=1234&condition=test var urlvar = jsPsych.data.urlVariables(); console.log(urlvar.subject) // logs "1234" console.log(urlvar.condition) // logs "test" ``` --- ## jsPsych.data.write ``` jsPsych.data.write(data_object) ``` ### Parameters Parameter | Type | Description ----------|------|------------ data_object | object | Object of `key: value` pairs to store in jsPsych's data storage as a trial. ### Return value Returns nothing. ### Description This method is used by `jsPsych.finishTrial` for writing data. You should probably not use it to add data. Instead use [jsPsych.data.addProperties](#addProperties). ### Examples ```javascript // don't use this! data should only be written once per trial. use jsPsych.finishTrial to save data. var trial_data = { correct: true, rt: 487 } jsPsych.data.write(trial_data); ```